While performing a vehicle door removal during extrication training last week, I caught the spreaders with the inside of my right thigh.  When the door latch separated from the nader bolt, it popped open, in turn pushing the spreaders back into my leg (yes, the picture is a human leg, not a chicken leg).  The spreader is the Hurst ML-32 which weighs approx. 53 lbs.
Normally, I lean into the tool enough to prevent being struck.  As you can see, it left a nice perfectly round bruise which took five days to surface.  I was wearing full turnout gear with eye protection.  I am thoroughly convinced that this prevented more serious injury, due to some padding provided by the turnout liner.